Shaded panel groove



April 30, 1963 R. l.. HUDSON SHADED PANEL GROOVE 4 Filed Jme 18, 1956 INVENToR. Robert L. Hudson BY' wh/fehead, Voq/g Lowe Pf@ JMJ a ma TTORNEYS United States Patent C) 3,087,269 SHADED PANEL GROOVE Robert L. Hudson, 4464 S. Washington St., Englewood, Colo. Filed lune f8, 1956, Ser. No. @2,008 1 Ciaim. (Cl. t1- 24) This invention relates to decorative surfacing of woodwork and more particularly to `decorative grooving in woodwork `and especially in paneling, and to methods and apparatus for forming the same. The p-rimary object of lthe invention is to provide novel and improved decorative grooving in wooden panels, and the invention will be hereinafter described with reference to such, altho-ugh it is to be understood that the scope of the invention could be extended to various other types of Wood constructions and Ito other materials having Woodlike 4surfaces.

The objects of the invention include the provision of a novel :and improved decorative groove in a wood panel which: is formed with a tempered, tight smooth-finished surface that requires no further finishing operations; is tempered to a shaded color darker than the normal color of the panel surface to give the groove a distinctive appearance and impression of depth; may be tempered to any selected degree of shading as `an incident of the groove formation; permits the panel to be finished as by a coat of varnish or the like as soon as it is grooved without the necessity of a preliminary special operation to apply tint or stain to the groove to olfset it from the panel surface; and, results in a neat-appearing iinal product that is adapted to be formed by simple low-cost manufacturing processes.

Other objects include the provision of a novel method and improved apparatus for forming decorative, tempered, shaded grooves in a wood panel which: permits the panels to be handled in any conventional manner that is required to cut ordinary unshaded surface grooves; requires no special steps nor operations in connection with the cutting of the decorative grooves in the panels; permits the shading of the grooves as an incident to the cutting of the grooves; involves simple, easy modification to conventional apparatus; :and permits the formation of tinted grooves in a simple, neat, quick, low-cost operation.

With the foregoing and other obje-cts in View all of which more fully hereinafter appear, my invention comprises certain novel and improved products, steps, constructions, and combinations of parts, elements, land operations as hereinafter described and as defined in the appended claim, and illustrated in preferred embodiment in the accompanying drawing in which:

FIGURE l is an end elevation view, somewhat diagrammatic in nature, of apparatus adapted to cut grooves in a wood panel moving therethrough.

FIGURE 2 is a side elevation view of the apparatus illustrated `at FIG. l.

FIGURE 3 is a fragmentary portion of the surface of a panel illustrating a decorative groove cut therein.

`FIGURE 4 is an enlarged isometric sectional fragment of the panel and groove cut therein, of the type illustrated yat FIG. 3, Ibut illustrating the nature of the surfacing of the groove required to temper and shade the groove in accordance with the invention.

lCC

FIGURE 5 is a fragmentary portion of a grooving saw such as illustrated :at FIGS. l and 2 and viewed from the indicated line 5 5 at FIG. l but on 1a greatly enlarged scale and modified to temper and shade the groove in accordance with the invention.

FIGURE 6 is a fragmentary sectional detail as viewed from the indicated line 6-6 -at FIG. 5.

FIGURE 7 is a face view of the cutting teeth of the saw as viewed from the indicated arrow 7 at FIG. 5.

FIGURE 8 is a fragmentary portion of .the saw `teeth as illustrated at FIG. 5 but on a greatly enlarged scale and showing the same as being set within a groove in a panel to illustrate the operative principle of the invention.

FIGURE 9 is a fragmentary isometric detail somewhat similar to FIG. 4 but illustrating `a modied form of groove.

The use of comparatively thin plywood panels has be- -come popular for finishing wall surfaces and the like because such panels `are low-cost, neat-appearing and easily installed units. To form decorative surfaces these plywood panels are usually made with :a core of comparatively strong wood such as Douglas r and with 1a face veneer of selected hardwood such as maple, mahogany or the like. To further enchance the decorative appearance of such plywood panels it has been found desirable to form grooves in the panels `according to selected patterns such as parallel lines, diamonds, squares, and the like. The usual form of groove is cut through the face veneer and into the core because the face veneer is cornparatively thin, `and it becomes necessary to cut into the core to provide proper depth even though the core may be a coarse grained wood of undesirable appearance. If a groove is cut in the face veneer only, it must necessarily be very shallow. However, appearance of depth may be obtained by shading the groove, but conventional tinting operations to accomplish this purpose are tedious and not practical.

Various types of apparatus have been developed to form such grooves in plywood panels, and such apparatus generally includes means for shifting the panels along a path and cutters adapted to contact the panel surface during such movement. The shifting means may be formed as a movable table or rollers or the like, and the plywood panels `are held in any conventional manner during such movement to remain in proper predetermined alignment with respect to the cutters. The cutters are generally high speed routers or saw-like units which may he specially designed mills, but they may also be formed by placing ordinary circular saws together. Such saws are easily obtained and are ideally suited for groove cutting.

The saws or other types of cutters are commonly formed in conventional manner with cutting teeth and drag teeth to cut and clean out the wood particles from the grooves. It is conventional practice to use pointed cutter teeth and to have a bottom rake of 4 or 5 degrees on each drag tooth lto properly clean out the grooves. These conventional cutters quickly and neatly remove the wood from the grooves as long as they are reasonably sharp, and operations of groove forming are generally performed in a smooth continuous manner. The tinting or shading operations are subsequent to the grove cutting opera-tions, and Whether performed as a tandem step in a continuous operation or as a subsequent independent operation are necessarily costly and time consuming.

With such in view the present invention was conceived and developed about the idea that it would be possible to perform a groove cutting and staining operation simultaneously. The invention comprises, in essence, a high speed rubbing action combined with the groo-ve cutting operation in a manner which permits the rubbing action to smooth, temper, and darken the grooves as they are being cut.

Referring more particularly to the drawing, FIGS. 1 and 2 represent, diagrammatically, apparatus for a grooving operation. A plywood panel P is carried upon rollers IS which are suitably actuated to move the panel along a path; and it is 4to be understood that the showin-g of the rollers is somewhat symbolic since endless belts, reciprocating tables and the like may be used to move the panel P. A suitable framework 16 is mounted above the rollers to support an arbor 17 and grooving saw 18 therein, ythe saw being mounted upon a shaft 19 which may be rotated at a suitable speed by any means, not shown. The height of the arbor 17 is established such that the saw cuts intoV the face veneer a depth suiiicient to form only a shallow groove 20 which is cut out responsive to movement of the panel P along the path defined by rollers 15. To maintain groove of constant dept-h regardless of the variation of panel thickness, suitable gages not shown may be mounted upon the framework 16 to bear against the surface of lthe plywood to raise or lower the saw slightly.-

The groove 20 is preferably triangular in section, as illustrated at FIG. 4, although it may be formed otherwise such as, for example, a semicircle Ztl' as illustrated at FIG. 9. It follows `that the grooving saw 18 must be ground for such shaping in a symmetrical manner to provide a symmetrical cut. One desirable arrangement of forming such a saw is Ito place two conventional saws together, face to face, as -lSR and ISL lillustrated at FIGS. 6 and 7. The invention will be hereinafter described as using a pair of saws so placed together, but it is to be understood that a single-piece grooving saw or other type of saw may be also built and used for the grooving operation in accordance with the concepts of the invention.

The Combined cutting and staining of the `grooves in a single operation is preferably effected by a grooving saw which includes -a plurality of cutter teeth 21 and rubbing teeth 22 spaced at regular intervals about the periphery of .the saw. The staggered arrangement of the cutting and raking teeth of conventional combination circular saws is ideally suited to form the cutter teeth 21 and the rubbing teeth 22, and only very simple modifications to conventional saws are necessary to effect this result. The combination saw blades 18K and ISL are set against each other tas a single un-it with their contacting faces defining the center of the saw. The teeth in each saw will then be ground to eliminate set land to conform with the shape of the groove. In such grinding narrow flats 2.3 are formed on the cutter teeth 21 and comparatively broad flats 24 are formed on the rubbing teeth 22, `and these flats are inclined either to the left or right of the dividing center to conform with the shape of the groove.

When these liats Aare tirst ground, by simple rotat-ion of a saw about its axis with the .teeth contacting a properly set grinding stone or wheel, their surfaces will define portions of the circular arc of rotation `of the saw. The flats 23 of the cutter teeth are made small as possible to minimize their burning action Jwith the leading cutting edges 25 but suitably sharpened. I-f desirable, the flats 23 may be further ground to provide for a slight bottom rake `from their leading .cutting edges but simply tiling down the tooth gullets to reduce the area of the iiats 23 on the cutter teeth is fully as satisfactory.

No further alterations are made to the broad ilats 24 .of the rubbing teeth 22 to provide for any bottom rake or clearance, and the entire `surface of the broad flats lies in and denes portions yof the circular arc Iof rotation of the saw, and it follows that all portions of this flat 24 will contact the face of a groove being cut by the saw. To prevent `any cutting, the leading edge 26 of each rubbing tooth is blunted and preferably rounded slightly as in the manner illustrated Iat FIG. 8.

Since the arcuate surfaces of the liats 24 lie in the arc of the saw periphery and contact the face of a groove by `all portions of this tlat, there will be a rubbing action of the flats against the wood surface ofthe groove. Whenever a rubbing tooth Z2 moves into the cut of the panel there will `actually be a slight compression of the fibres by the tooth as well as a rubbing action. :It |follows that whenever a rubbing tooth 2,2 moves into the cut of the panel, the fibres of the panel will be compressed by the flat 24 of the rubbing tooth instead `of being cut.

Since the saws will rotate lat relatively high speeds the movement of the rubbing teeth Z2 across the tibres will create substantial frictional heat, rand the pressure against the fibres will actu-ally burn or scorch the Ifibres. Such burning -combined with compression will smooth land close the pores of the wood to temper the surface of the groove to provide for a darkened, hardened iinish 27 in the groove. This rubbed surface in the groove forms an improved product eliminating the need for subsequent tinting operations to offset the groove in the panel, and it appears that the nature of the rubbing results in substantially the same type of product regardless of the direction of the groove cut compared with the grain of the wood, since the rubbing effectively compresses the wood `libres into the closed pore surface 27.

The shading of the groove is effected directly by the degree of burning or scorching of the groove and may be easily controlled by simple adjustments of the speed of the saw and speed of panel movement past the saw as a groove is being cut. The rubbed, scorched surface may thereby vary from a light colored tint scarcely darker than the natural wood to .a very dark brown almost black appearing color.

After such a shaded groove is cut in a panel, the surface may be sanded or other-wise prepared -for nishing without touching the groove since it will be `almost glassy smooth. The prepared panel may then be given -a inishing coat of varnish, lacquer, or oil without any attention to the groove. The groove will then 4appear to be substantially darker than the surface of the panel to give a desired illusion of depth.

While the actual rubbing operation may be electively completed in the manner and with apparatus hereinabove described, the actual improved rubbed surface may be obtained by slight vari-ations of method. For example, two saws may be placed in tandem, the iirst saw for cutting and the second Ifor rubbing, with the speed of the rubbing saw being correlated with the movement of the panel to provide for the desired degree of scorching or burning, as the :libres are compressed into a slick surface after being cut.

While I have described my invention in considerable detail, it is obvious that others skilled in the art can devise and build similar products, and by operations, an-d with apparatus all of which are lwithin the spirit and scope of my invention, hence it is my desire that my protection extend not to the constructions herein illustrated and described, but only by the proper scope of the appended claim.

I claim:

As an article of manufacture, a plywood panel including a wooden face veneer, said veneer having a decorative groove therein, said groove having a depth less than the thickness of said veneer, the surface libres of said groove having a `greater density than the surrounding tbres of said veneer, said surface libres also being scorched, whereby the surface of said groove presents a contrasting color and appearance with respect to the surrounding surface of said veneer.

References Cited in the file of this patent UNITED STATES PATENTS Gyles June 25, 1872 Shannon July 18, 11893 Lyon May 20, 1902 Hayes Dec. 2, 1902 Groves Mar. 4, 1913 6 Willson Oct. 24, 19116 Sleolnk Sept. 6, 1927 Goldman Feb. 18, 1936 Raes Jan. 2, 1940 Deskey June 9, 1942 Frater Apr. 111, 1944 Bailey Nov. 28, 1944 Faulk Mar. 20, 1951 Sobel July 5, 1955 Schubert Jan. 22, 1957 Leonardson et lal. Feb. 26, 1957 

